When taping a drywall corner, make sure not to use the taping compound directly out of the pail, and focus on mudding only one side of the corner at a time. Make sure to embed the tape completely, and do not leave any dry tape on the wall.
To mud one side of the drywall corner at a time, coat one side of each corner, and let it sit overnight to dry before troweling compound on the adjacent sides. Spread a 3-inch band of joint compound across the tap on one side of the corner, and then smooth it over with a taping knife. Press the edge of the knife to the drywall to produce a feathered edge; this reduces the need for sanding later on. When using this technique, avoid leaving too much joint compound over the tape since material buildup makes it harder to fit moldings or baseboard to the wall.
If there are metal corner beads present, apply paper tape over the metal edge after nailing the bead to avoid cracking. Another method of avoiding eventual cracking is using the special corner bead that is attached by joint compound rather than nails. Also, if any drywall tape becomes bubbled or loose, cut out the damaged area with a utility knife, remove the tape, fill the recess with setting compound, and apply a new coat of joint compound over it for a smooth result.